Workstation of a Rotor Spinning Machine Comprising a Cleaning Unit and Method for Operating Such a Device

ABSTRACT

The invention relates to a workstation of a rotor spinning machine including a spinning rotor ( 3 ) mounted so as to be rotatable about a rotational axis (X), wherein the workstation comprises a cleaning unit ( 1 ) including a mechanical cleaning element ( 2 ) for cleaning an inner surface ( 21 ) of the spinning rotor ( 3 ). According to the invention, it is provided that the cleaning element ( 2 ) is movably arranged on the workstation in such a way that, starting from a neutral position in which the cleaning element ( 2 ) is not in contact with the spinning rotor ( 3 ), the cleaning element ( 2 ) can be moved into various cleaning positions for various inner diameters of the spinning rotor ( 3 ), wherein the cleaning element ( 2 ), in the particular cleaning position, is in contact with the inner surface of the spinning rotor ( 3 ).

The present invention relates to a workstation comprising a rotor spinning machine including a spinning rotor mounted so as to be rotatable about a rotational axis, wherein the workstation comprises a cleaning unit including a mechanical cleaning element for cleaning an inner surface of the spinning rotor.

Moreover, a method is provided for cleaning an inner surface of a spinning rotor—which is mounted on a workstation of a rotor spinning machine so as to be rotatable about a rotational axis—with the aid of a cleaning unit of the workstation, wherein the cleaning unit includes a mechanical cleaning element.

Rotor spinning machines generally consist of a plurality of workstations, which are usually adjacently arranged. An operation is carried out at each of these individual workstations. For example, in a first step, a supplied sliver is separated into its individual fibers with the aid of an opening unit. In a further step, the separated fibers are then spun in a spinning rotor to form a yarn. In a subsequent operation, a downstream winding device winds this yarn onto a package.

The spinning rotor of the workstation is a component which is susceptible to trash for design- and method-related reasons. Since it is technically not yet possible to keep the sliver free from foreign matter or any other trash, it is necessary to regularly maintain and clean the spinning rotor. For this purpose, a maintenance flap or a closing device is usually provided on the workstation, via which the spinning rotor is accessible from the outside after the maintenance flap or the closing device has been opened. Finally, this allows for easy access to the spinning rotor.

In order to further increase the degree of automation of such workstations, an automatic cleaning unit is usually mounted on the workstation or on a service robot of the rotor spinning machine.

DE 10 2005 025 786 A1, for example, describes a textile machine, in particular a rotor spinning machine, comprising a plurality of workstations, wherein each of these workstations includes a separate cleaning device. The cleaning device can be arranged either on or in a housing of the workstation as well as on or in a closing device thereof. The cleaning device contains a cleaning element, wherein this cleaning element can be transferred into a cleaning position with the aid of a single drive. The corresponding movement can encompass a rotational movement about a rotational axis of the cleaning element. In the cleaning position, the cleaning element is engaged with a rotor groove, in particular via a mechanical scraper. Further prior art is found in DE 26 18 094 A1 or in DE 39 11 946 A1.

The problem addressed by the present invention is that of refining the known prior art.

The problem is solved by a workstation of a rotor spinning machine as well as a method having the features of the independent claims.

The invention relates to a workstation of a rotor spinning machine including a spinning rotor mounted so as to be rotatable about a rotational axis, wherein the workstation comprises a cleaning unit including a mechanical cleaning element for cleaning an inner surface of the spinning rotor.

According to the invention, it is provided that the cleaning element is movably arranged on the workstation in such a way that, starting from a neutral position in which the cleaning element is not in contact with the spinning rotor, the cleaning element can be moved into various cleaning positions for various inner diameters of the spinning rotor, wherein the cleaning element, in the particular cleaning position, is in contact with the inner surface of the spinning rotor.

The neutral position of the cleaning element is arranged outside the spinning rotor, in particular outside a closing device of a housing accommodating the spinning rotor. Additionally, the neutral position can be located in a separate protective device, so that the cleaning element cannot become damaged during the normal operation of the workstation.

The cleaning position, however, is located within the spinning rotor, wherein the precise cleaning position is defined by the diameter of the spinning rotor. In this cleaning position, the mechanical cleaning element is in contact with an inner wall, in particular with the rotor groove, of the spinning rotor.

The cleaning effect of the cleaning unit arises primarily due to the rubbing or scraping of the cleaning element on the inner wall of the spinning rotor, wherein the intensity of the rubbing or scraping is determined via the contact force of the cleaning element.

It is particularly advantageous when the cleaning unit is designed as a structural unit, i.e., as a self-contained module. Thus, the module is to be detached from the remaining sections of the workstation or correspondingly easily installed as an entire unit, with the aid of a few work steps, for example, by releasing a quick connector or a few screws, for the purpose of maintenance, installation, or exchange. This reduces the time required for installation/removal and, in the event of an error message, provides for a shorter downtime of the cleaning unit or the workstation.

It is particularly advantageous when the power supply of the cleaning unit is carried out with the aid of a contact system or a contactless energy transmission or a comparable energy transmission from the workstation. Preferably, such an interface for the energy transmission is arranged on the workstation in the region of the rotor cleaning. It is also advantageous when control commands of the control system of the rotor spinning machine or of the workstation comprising the cleaning unit can be transmitted to the cleaning unit via this interface.

Moreover, it is advantageous when the cleaning unit comprises a first drive, which moves the cleaning element between the neutral position and the particular cleaning position. The first drive can also carry out only a portion of the sequence of movements from the neutral position to the cleaning position and a second drive (described in greater detail in the following) can carry out a second portion of the sequence of movements to the cleaning position. Preferably, the cleaning element includes a cleaning arm, which is connected to the first drive and on whose end facing away from the first drive a cleaning scraper or a cleaning brush is arranged.

It is particularly advantageous when the first drive comprises an electric motor, preferably a stepper motor or a servomotor, wherein the electric motor is designed for swiveling the cleaning element about a rotational axis. As a result, it is possible to achieve a precise control of the contact force of the cleaning element, in the cleaning position, onto the spinning rotor, in particular onto the rotor groove, wherein the cleaning position is reached by overshooting the end position of the cleaning element. Due to this overshooting or over-rotating of the cleaning element with respect to the end position, a certain contact force is generated by a preferably present spring effect of the cleaning element. Due to an appropriate control software, the level of contamination and/or the wear of the cleaning element can be ascertained with the aid of the contact pressure and the angular position of the cleaning element in the cleaning position as compared to the neutral position. Moreover, error feedback is possible with the aid of such a drive in the event of unexpected events, for example, due to foreign objects in the spinning rotor or due to an elevated or insufficient contact pressure.

Moreover, it is advantageous when the rotational axis of the cleaning element and the rotational axis of the spinning rotor extend in parallel, askew, or in a common plane obliquely with respect to one another. This makes it possible to easily insert or swivel the cleaning element into the spinning rotor, since the upper opening of the spinning rotor is often substantially smaller than its diameter in the region of the rotor groove. A skew position of the rotational axes of the cleaning element and of the spinning rotor would result, for example, in a multidimensional sequence of movements of the tip of the cleaning element with respect to the plane of the spinning rotor. In other words: The skew position would result, for example, in a sequence of movements comparable to that of a corkscrew.

It is also advantageous in this context when the cleaning element is mounted in such a way that the angle of the rotational axis of the cleaning element with respect to the rotational axis of the spinning rotor is changeable. As a result, substantially greater flexibility with respect to the diameter of the spinning rotor to be cleaned would be established. Additionally, this facilitates the insertion of the cleaning element into the spinning rotor.

It is also advantageous when the drive comprises a linear drive, preferably in the form of a pneumatic cylinder, with the aid of which the cleaning element can be moved, preferably and at least in sections, in a straight movement. Preferably, the pneumatic cylinder is arranged in such a way that the cleaning element is movable in parallel, orthogonally, or askew with respect to the rotational axis of the spinning rotor. The linear drive can also be arranged in such a way that the cleaning element is swivelable about a further rotational axis, so that the angle between the first rotational axis and the rotational axis of the spinning rotor is changeable.

It is particularly advantageous when an energy accumulator, preferably in the form of a spring, is assigned to the drive, wherein the energy accumulator is arranged in such a way that the cleaning element can be moved from its cleaning position into its neutral position, or vice versa. It is also advantageous when the energy accumulator is arranged in such a way that, with the aid thereof, at least a portion of the sequence of movements of the cleaning element from the cleaning position to the neutral position, or vice versa, can be carried out. As a result, the drive configuration or the drive of the cleaning unit can be more simply configured. In addition, this makes it possible to utilize single-acting pneumatic cylinders, i.e., pneumatic cylinders without a restoring mechanism or without a pneumatic line for a restoring mechanism.

Moreover, it is also advantageous when a guide, in particular in the form of a slotted guide, is associated with the cleaning unit, wherein this guide is designed in such a way that it carries out at least a portion of the sequence of movements of the cleaning element from its neutral position into its cleaning position. It is feasible that the guide is designed to be linear, i.e., for a straight sequence of movements of the cleaning element. It is also feasible that the guide is utilized for rotating or tilting the first drive about a rotational axis or rotating or tilting the cleaning element itself. This would allow for a more complex sequence of movements in connection with a relatively simple drive concept.

In this context, it is also advantageous when the guide comprises at least two guide sections. These guide sections extend preferably offset and/or slanted with respect to one another and, in this way, make it possible to move the cleaning element in different directions. The guide sections are designed, preferably and at least in sections, in such a way that a linear movement and/or a rotation and/or an inclination of the cleaning element are/is effectuated. As a result, it is possible to further simplify the drive concept without losing the flexibility with respect to the various inner diameters of the spinning rotor.

Moreover, it is advantageous when this guide includes an adjustment option for limiting and/or changing the sequence of movements in one or multiple directions, wherein this limitation is configured as a stop, as a screw limitation, or as an inlay limiter (in other words: a component that is inserted into the guide and forms a geometric limitation). The limitation can be designed in such a way that the end position and/or one or multiple intermediate positions of the cleaning element are/is changeable. Preferably, this limitation is designed in such a way that it can be carried out from the outside, i.e., without removing the cleaning unit itself, when the cleaning unit has been installed on the workstation and/or during the operation thereof. This would increase the flexibility with respect to the end position and the insertion movement of the cleaning element into the spinning rotor, whereby it would be possible to cover a greater number of spinning rotors having different diameters using the same cleaning unit.

It is also advantageous when the cleaning unit comprises a second drive, wherein this drive is designed, in particular, as a linear drive or as an electric motor according to the preceding description. This is arranged, in particular, on the first drive in such a way that, in combination with the first drive, a swiveling of the cleaning element about multiple rotational axes, a displacement in multiple movement directions, which are slanted and/or offset with respect to one another, or any combination thereof can be carried out. As a result, it is possible that the sequences of movements can be adjusted even more precisely and, in particular, automatically with the aid of a targeted control.

Additionally, it is advantageous when the cleaning unit comprises a pneumatic suction and/or blowing unit, wherein this is designed for removing foreign material located on and/or in the spinning rotor. The pneumatic suction and/or blowing unit is preferably arranged in the region of the cleaning element, so that the foreign material, in particular fiber residue, detached from the spinning rotor with the aid of the cleaning element can be removed from the inner region of the spinning rotor. This allows for an efficient removal of loose foreign material, in particular during the insertion and/or withdrawal of the cleaning element into or out of the spinning rotor.

In addition, a method is provided for cleaning an inner surface of a spinning rotor—which is mounted on a workstation of a rotor spinning machine so as to be rotatable about a rotational axis—with the aid of a cleaning unit of the workstation, wherein the cleaning unit includes a mechanical cleaning element.

According to the invention, the cleaning element is moved into a cleaning position starting from its neutral position, which is arranged outside the spinning rotor, in particular outside a closing device of a housing accommodating the spinning rotor, and in which the cleaning element is not in contact with the spinning rotor. The cleaning position is selected depending on the spinning rotor currently utilized in the workstation, in particular depending on its inner diameter. In principle, multiple different and mutually deviating cleaning positions are therefore available, which can be approached depending on the spinning rotor.

The adjustment of the cleaning position is carried out, in particular automatically, by the central control system of the rotor spinning machine or a control system of the particular workstation, although it can also be carried out manually by the operating personnel when necessary and/or for the purpose of control.

Moreover, it is advantageous when the cleaning position is defined by the inner diameter of the spinning rotor and is selected by the control system of the spinning machine. The cleaning position is selected in such a way that the cleaning element, in its end position in the spinning rotor, is in contact with the rotor groove and/or the side wall of the spinning rotor. For the purpose of cleaning, the cleaning element is pressed against the surface to be cleaned with the aid of a defined force, wherein this force can be variably adjusted during a cleaning process. In particular, it would be feasible to move the cleaning element against the inner wall of the spinning rotor in a pulsing manner with the aid of the first drive, which is preferably designed as a stepper motor. The effect of the cleaning element is comparable in this case, in principle, to that of a pneumatic hammer. Trash adhering to the inner wall is particularly effectively detached as a result.

In this context, it is particularly advantageous when the control system of the rotor spinning machine ascertains the power consumption of the first and/or the second drive and, in the case of rotary drives, the revolutions or steps or, in the case of linear motors, the distance from the starting position to the actual position. As a result, it is possible to determine the force applied on the cleaning element or the contact force of the cleaning element onto the inner wall of the spinning rotor and to control the drive according to the contact force. In addition, deviations with respect to standard values can be detected during the cleaning, such as damage to the cleaning element or larger foreign objects in the spinning rotor.

It is particularly advantageous when the cleaning element is moved from its neutral position into a first position in a first movement. The first position can already be the cleaning position. It is also feasible, however, that the first position is located at any point in the sequence of movements from the neutral position into the cleaning position.

It is also advantageous when the cleaning element is moved from its first position into a second position with the aid of a second movement, The second position is the end position and, therefore, the cleaning position, In addition, the movement direction of the cleaning element during the second movement differs, at least in sections, from the movement direction of the first movement.

It is feasible that the first movement is carried out by the first drive and the second movement is carried out by a second drive, In this context, it is also feasible that no specific first position is present, due to a superposition of the first and the second movements, and so the cleaning element is moved directly into the cleaning position in a movement consisting, for example, of a simultaneous rotation and swiveling in two different directions.

Moreover, it is advantageous when the movement direction of the cleaning element during the first and/or the second movement(s) extends in a straight line, at least in sections.

It is particularly advantageous when the cleaning element is moved via its first movement into the interior of the spinning rotor and via the second movement into its cleaning position. In the cleaning position, the cleaning element is then in contact with the inner wall of the spinning rotor, in particular in the region of the rotor groove and/or the side wall of the spinning rotor, The first movement can be carried out already during the opening of the closing device of the housing accommodating the spinning rotor. After the spinning rotor has been cleaned, the cleaning element follows the sequence of movements of the advancement up to the cleaning position in the opposite direction, in order to reach its neutral position again.

Moreover, it is advantageous when the first and/or the second movement(s) are/is a reciprocating or swivel movement. Preferably, the reciprocating movement extends in parallel to or at an acute angle with respect to the rotational axis of the spinning rotor. A swivel movement can preferably be carried out in such a way that the angle at which the cleaning element is situated with respect to the rotational axis of the spinning rotor can be changed.

It is also advantageous when the movement is controlled by a guide. In particular when the guide is designed as a slotted guide, a simple embodiment and adaptation of the sequence of movements to the geometry of the spinning rotor is possible. The movement of the cleaning element through the guide with the particular characteristic movement properties, such as movement direction, speed, and/or acceleration, is carried out with the aid of the drive or the drives and is controlled with the aid of the central control system of the rotor spinning machine or the corresponding workstation.

It is advantageous when the cleaning element is first moved from its neutral position into one of multiple possible cleaning positions with the aid of a drive of the cleaning unit and, after the end of the cleaning process, is guided back into its neutral position with the aid of an energy accumulator of the cleaning unit, for example, in the form of a spring element. It is also feasible in this context that the spring element effectuates or assists only a portion of the sequence of movements, for example, into one of the intermediate positions.

It is also advantageous when the cleaning element is moved from its neutral position into one of multiple cleaning positions with the aid of an energy accumulator and is guided back into the neutral position, from the cleaning position, with the aid of a drive.

By utilizing an energy accumulator, a simplification of the drive concept, for example, with the aid of a single-acting pneumatic cylinder, can therefore be achieved. Additionally, this results in a reduction of the manufacturing costs.

In an exemplary embodiment, a sequence of movements could appear as follows: In a first step, the cleaning element is raised from its neutral position in parallel to the rotational axis of the spinning rotor. In a second step, the cleaning element is swiveled about its rotational axis into the center of the spinning rotor.

In a further step, the cleaning element is lowered again, whereby the tip of the cleaning element is preferably located at the level of the rotor groove. In a final step, the cleaning element is swiveled once again about its rotational axis further in the direction of the rotor groove until the cleaning element is in contact therewith. Due to the evaluation of the drive parameters, the contact force of the cleaning element can be adapted for the cleaning of the rotor groove. After the cleaning process has ended, the sequence of movements is carried out similarly to the insertion in the opposite direction.

Moreover, it is advantageous when the rotor cleaning is carried out at least partially during the rotor coastdown. In this context, it is also feasible that the central control system of the rotor spinning machine or of the corresponding workstation adapts the rotational speed of the spinning rotor to the level of contamination or to the contact pressure of the cleaning element. Preferably, various coastdown and/or start-up methods, for example, with the aid of a (variable) ramp function, of the spinning rotor drive are utilized. Therefore, the cleaning of the spinning rotor can also be carried out without completely stopping the spinning rotor, which results in a reduction of the downtime of the spinning rotor.

It is also feasible that the rotor is initially stopped before the cleaning, in order to be able to safely open a rotor cover closing the rotor during the spinning operation. Subsequent to the opening, the rotor can be set into rotation again, wherein this can take place before, during, or after the movement of the cleaning element into its cleaning position.

In this context, it is also advantageous when the spinning rotor is brought to a standstill or the drive of the spinning rotor is throttled to a standstill before the spin box is opened. After the cleaning element has been inserted, it is particularly advantageous when the spinning rotor is accelerated into an appropriate rotational speed range according to its level of contamination. During a cleaning process, the final rotational speed of the spinning rotor can be variably configured, so that, due to a brief acceleration and deceleration of the spinning rotor, an additional slight vibration is generated, which improves the cleaning effect of the cleaning element.

Finally, it is also advantageous when a pneumatic suction and/or blowing arrangement is activated in the cleaning position or in an intermediate position between the neutral position and the cleaning position of the cleaning element, wherein the activation of the pneumatic suction and/or blowing arrangement can take place during the insertion into the spinning rotor as well as during the withdrawal from the spinning rotor. Due to this additional cleaning option, loose foreign materials in the spinning rotor as well as in the closer surroundings around the spinning rotor (upon activation of the suction and/or blowing arrangement outside the spinning rotor) are removed.

Further advantages of the invention are described in the following exemplary embodiments. Wherein:

FIG. 1 shows a side view of a spinning rotor comprising a cleaning unit in the neutral position,

FIG. 2 shows a side view of a spinning rotor comprising a cleaning unit during the insertion/withdrawal,

FIG. 3 shows a side view of a spinning rotor comprising a cleaning unit in the cleaning position,

FIG. 4 shows a top view of a spinning rotor comprising a cleaning unit,

FIG. 5 shows a side view of a cleaning unit,

FIG. 6 shows a side view of a cleaning unit, and

FIG. 7 shows a side view of a cleaning unit.

In the following description of the figures, the same reference signs are utilized for features which are identical and/or at least comparable in each of the various figures. The individual features, their embodiment and/or mode of operation are explained in detail usually only upon the first mention thereof. If individual features are not explained in detail once more, their embodiment and/or mode of operation correspond/corresponds to the embodiment and mode of operation of the features which act in the same way or have the same name and have already been described.

FIGS. 1, 2, and 3 schematically show a sectional view, as an example, of an embodiment variant, according to the invention, of a workstation comprising a cleaning unit 1 and a spinning rotor 3. The representation omits all other attachments of a workstation, such as a sliver feed unit, since appropriate workstations of a rotor spinning machine are known, in principle, from the related art. The spinning rotor 3 is rotated about the axis X during the operation of a central or single drive, wherein the rotational speed is controlled by a spinning machine control system (not represented) or a workstation-specific control system. After the sliver has been moved through a sliver feed unit (not represented) into the opening roller (also not represented), the individual fibers enter the spinning rotor 3 in which they impact the rotor groove 4 rotating at high speed. Due to the geometry of the spinning rotor 3 and its speed, the fibers are spun into a yarn.

In this spinning process, it is unavoidable that foreign material and other fiber reside accumulate in the spinning rotor 3. The level of contamination increases sharply after a certain period of operation, primarily in the rotor groove 4. Therefore, the quality of the spun yarn decreases or thread breakages occur already in the spinning rotor 3. For this reason, the rotor groove 4 must be cleaned at regular intervals. This is possible due to the represented cleaning unit 1.

If a cleaning process is necessary, the appropriate control system reduces the rotational speed of the spinning rotor 3 and opens a closure (not represented) of a spin box enclosing the rotor. Additionally, the control system actuates the drive 12, 13, 14, 15 of the cleaning unit 1, in order to start the cleaning process.

In the present exemplary embodiment, the cleaning unit 1 comprises a cleaning element 2, a first drive 12, 13, and a second drive 14, 15.

In the present example, the cleaning element 2 is divided into four regions. The first region 8 of the cleaning element 2 is utilized as a fastening means for mounting on the first drive 12. The second region 9 and the third region 10 are designed to be linear in this case and extend, with respect to FIGS. 2 and 3, horizontally (second region 9) from the first region and then vertically (third region 10) to the fourth region 11. The fourth region 11 is the tip of the cleaning element 2, with the aid of which the cleaning element 2 can be brought into contact with the spinning rotor 3. All four regions 8, 9, 10, 11 or any combination of one or multiple regions 8, 9, 10, 11 can be made of an elastic material.

The first drive 12 comprises an electric motor, for example, a stepper motor 15, with the aid of which the cleaning element 2 is mounted so as to be rotatable about the rotational axis Y, which preferably extends in parallel to the rotational axis X of the spinning rotor 3. The first drive 12 can therefore swivel the cleaning element 2 perpendicularly to the rotational axis X of the spinning rotor 3.

In this context, it is also feasible, of course, that the rotational axis X of the spinning rotor 3 and the rotational axis Y of the cleaning element 2 extend askew with respect to one another. The second drive 13 comprises a linear drive 14, for example, in the form of a double-acting pneumatic cylinder. The double-acting pneumatic cylinder can change the height offset between the cleaning element 2 and the spinning rotor 3, in order to ensure a problem-free insertion of the cleaning element 2 into the spinning rotor 3. The height offset of the cleaning element 2 must be at least as great as the greatest height offset between the normal position of the cleaning element 2 and the upper edge of the spinning rotor 6.

In a first step after the spinning machine control system has started the cleaning process, the cleaning element 2 is raised by the linear drive to such an extent that the cleaning element 2 is located above the upper edge of the spinning rotor 6. In a second step, the cleaning element 2 is swiveled about the rotational axis Y by the stepper motor 15, so that the cleaning element 2, as viewed in the top view, comes to rest above the spinning rotor 3 (cf. also FIG. 4). In a third step, the linear drive 14 lowers the cleaning element 2 into the interior space 5 of the spinning rotor 3, in which the cleaning element 2 is brought into contact with the rotor wall 7 or the rotor groove 4 with the aid of a further swiveling process. Due to the fact that the spinning rotor 3 is still rotating, fixed foreign material is mechanically removed from the spinning rotor 3 with the aid of a scraping process. The rotational speed of the spinning rotor 3 can be held constant by the spinning machine control system during the cleaning process, although it can also be variably adapted (depending on the level of contamination). In so doing, the spinning machine control system can determine, for example, by reading out the motor parameters, i.e., the angular position of the cleaning element 2 and/or the voltage draw and the current draw, the extent to which the cleaning element 2 has been worn or whether errors occur during the cleaning.

After the trash has been removed from the rotor groove 4, loose foreign material can be additionally removed from the spinning rotor 3 with the aid of a suction and/or blowing device (not represented here) associated with the cleaning element 2. The movement of the cleaning element 2 back into the neutral position is carried out inversely with respect to the movement from the neutral position into the cleaning position.

A schematic top view of a workstation comprising a spinning rotor 3 and a cleaning unit 1 is represented in FIG. 4. The configuration of the cleaning unit 1 and the sequence of the cleaning are basically identical to the embodiment variant shown in FIGS. 1, 2, and 3. In the variant shown here, it would also be feasible, however, that the lifting mechanism, i.e., the pneumatic cylinder from FIGS. 1, 2, and 3, is replaced by way of positioning the two rotational axes, i.e., the rotational axis Y of the cleaning element 2 and the rotational axis X of the spinning rotor 3, askew with respect to one another. As a result, due to the rotational movement of the cleaning element 2, a height offset of the tip of the cleaning element 2 additionally results from the movement out of the neutral position into the cleaning position and back, whereby the cleaning element 2 can be moved, without contact, over the upper edge of the spinning rotor 3 or its rotor wall 7.

FIG. 5 and FIG. 6 show an embodiment variant of a cleaning unit 1 similar to the preceding description. In this case as well, the cleaning unit 1 comprises a cleaning element 2 and a first drive 12 according to the preceding figures. The difference from the preceding variants is that, in addition to a first rotational axis Y, a second rotational axis Z is also present. The height offset necessary for moving the cleaning element 2 over the upper edge of the spinning rotor 3, without contact, is achieved, in this case, via a swiveling about the second rotational axis Z. For this purpose, a second drive in the form of a linear drive 14 is associated with the cleaning unit 1, which swivels the cleaning element 2 and its first drive 12 about the second rotational axis Z with the aid of a retraction and an extension. The linear drive 14 preferably comprises a single-acting pneumatic cylinder including an energy accumulator associated with the pneumatic cylinder, wherein the energy accumulator preferably consists of a compression or tension spring (not represented).

FIG. 7 schematically shows a sectional view of a guide 16 for a cleaning unit 1 of a workstation of a spinning machine. In this exemplary embodiment, this guide 16 is designed as a slotted guide 17. A special drive for guiding the cleaning unit 1 with the aid of the gate 17 is not represented in this figure. In this example, the gate 17 is subdivided into three sections, wherein the first section 18 and the third section 20 are utilized for the horizontal guidance and the second (middle) section 19 is utilized primarily for the vertical guidance. In this way, with the aid of a single drive, the complete insertion and withdrawal movement of the cleaning element 2 can be implemented without dispensing with the adaptability with respect to the rotor diameter. The adaptation to the rotor diameter takes place via the holding point in the guide in the third section 20.

The present invention is not limited to the represented and described exemplary embodiments. Modifications within the scope of the claims are also possible, as is any combination of the features, even if they are represented and described in different exemplary embodiments.

LIST OF REFERENCE CHARACTERS

-   -   1 cleaning unit     -   2 cleaning element     -   3 spinning rotor     -   4 rotor groove     -   5 interior space of the spinning rotor     -   6 upper edge of the spinning rotor     -   7 rotor wall     -   8 first region of the cleaning element     -   9 second region of the cleaning element     -   10 third region of the cleaning element     -   11 fourth region of the cleaning element     -   12 first drive     -   13 second drive     -   14 linear drive     -   15 stepper motor     -   16 guide     -   17 slotted guide     -   18 first section of the guide     -   19 second section of the guide     -   20 third section of the guide     -   21 inner surface     -   X rotational axis of the spinning rotor     -   Y rotational axis of the cleaning element     -   Z second rotational axis 

1. A workstation of a rotor spinning machine including a spinning rotor (3) mounted so as to be rotatable about a rotational axis (X), wherein the workstation comprises a cleaning unit (1) including a mechanical cleaning element (2) for cleaning an inner surface (21) of the spinning rotor (3), characterized in that the cleaning element (2) is movably arranged on the workstation in such a way that, starting from a neutral position in which the cleaning element (2) is not in contact with the spinning rotor (3), the cleaning element (2) can be moved into various cleaning positions for various inner diameters of the spinning rotor (3), wherein the cleaning element (2), in the particular cleaning position, is in contact with the inner surface of the spinning rotor (3). 2-21. (canceled) 